Telephone system



Dec. 23, 1930. R. F. STEHUK 1,786,410

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Dec. 23, 1930. R. F. sTEHLlK 1,786,410

TELEPHONE SYSTEM Original Filed Aug. 27. 1927 6 Sheets-Sheet 6 o o l o o N 25 O\\ OMV I'Hr @if I 556mm Patented Dec. 23, 1930 UNITED STATES PATENT oFFlcs RUDOLPH F. STEHLIIK, 0I CHICAGO, ILLINOIS, ASSIGNOR T0 RESERVE HOLDING COM- PANY, 0F KANSAS CITY, MISSOURI, A CORPORATION OF DELAWARE TELEPHONE SYSTEM Application led Augut 2 7, 1927, Serial No. 215,793. Benewed'April 9, 1930.

The present invention relates to telephone systems in general, but is concerned more particularly with multi-ofce telephone systems including both automatic and manual ofIices.

The broad general object of the invention is the production of new and improved arrangements for handling calls originating in automatic offices and intended for lines ter minating in manual oices. More particularly, the invention is especially applicable to systems employing call indicators in the manual oices which are set in response to imulses transmitted from an automatic oiice y a register sender.

One object of the invention is the production of suitable arrangements including preselecting finders for associating the registersender equipment with trunk lines that handle calls to the manual ofiice, whereby the necessity for eXtra hunting time is eliminated and the loss of calls due to this source is prevented. In this respect, the present invention may be said to be an improvement on' or a` modification of the arrangement shown in Patent No. 1,559,7 36, granted Nov. 3, 1925 to Bellamy et al.

A feature of the invention lies in the arrangement whereby an interoice trunk line from an automatic office to a manual office is not taken for use until all digits in the number to be transmitted to the manual oiiice havel been registered and the apparatus is ready to retransmit the number. By this arrangement, a material reduction in the holding time of the trunk lines is effected, which retil they have-been preselected in the manual office. With this arrangement in use, the

switching equipment in the automatic oce passes over the non-preselected trunk lines and selects only a trunk line that has been preselected.

A further feature of the invention lies in the arrangement incidental to the preselecting arrangement whereby the vcord circuits at the operators position are preselected in regular rotation, with the result that the operator can locate the next cord to be used more readily than if the cords were taken for use more or less promiscuously.

According to another feature of the invention, the two independently operable finders in the manual office, one for each register, are providedwith separate test conductors and associated arrangements so that either 4finder cannot preselecta trunk after it has been preselected by the other.

Another object of the invention is the production of new and improved arrangements for transferring quickly a number from the automatic oiiice to the registering equipment in the manual office without sacricing reliability, and at the same time using simple circuit arrangements and standard equip' ment. This object is attained byy providing circuit arrangements .such that two digits may be transmitted simultaneously, one over ach talking conductor of the interoiiice trunk ine.

It is a further object of the invention to provide circuit arrangements such that the equivalent of full metallic impulse circuits is obtained. In order to accomplish this object, arrangements have been provided so that when two digits of equal length are transmitted, the impulsing circuit is thru the two conductors of the trunk line in series and independent of a ground connection except in the manual office, special holding arrangements being provided for preventing the response of one of the receiving relays while the remaining portion of a long digit is being transmitted over one of the conductors in case the two digits to be transmitted simultaneously are of unequal length.

There are a number of other objects and features ofthe invention, which are more or less incidental to the foregoing, being concerned more'or less with the circuit details involved carrying out the main objects of the invention. The various objects and features of the invention will be understood best from the following description in connection with the accompanying drawings comprising Figs. 1J?.

Referring now to the drawings, Figs. 1&6 are circuit diagrams showing so much of the equipment in a telephone system embodying the features of the invention as is necessary tor the invention to be understood, and Fig. 7 is a layout drawing showing the way in which the sheets of drawings should be arranged in order to be understood best.

Figs. 1 3, taken together, show the trunking and switching equipment necessary to set up a connection from the automatic substation A. to the manual 'substation B. Figs. 4.- and 5 show the registering and sending equipment in the automatic oi'ce, and Fig. 6 snows the registering and call-indicating equipment in the manual oihce.

Fig. l shows the line switch LS individual to the line of substation A. The oihce selector ()S, accessible to the line switch LS, has access, on one level, to a number of repeaters, such as R. 7lfhe trunk lines with which the repeaters are associated are the trunk lines thru which the calls are extended from the automatic oce to the manual office containing the equipment shown in Figs. 5 and 6. Fig. l shows also' the finder F, which is of the preselecting type and is controlled from the equipment shown in Fig. 4.. This finder associates the register sender such as that shown in Figs. i and 5 with the re\ peater R.

The trunk line extending from the repeater R, Fig. 1, terminates in the secondary switch SS, Fig. 2. rlhis secondary switch operates at the proper time and selects a trunk line, such as the trunk line TL extending to the manual office.

Fig. 3 shows the cord circuit CC in which the inter-ofiice trunk line TL terminates. |The cord circuit CC ends in a plug P which may be inserted in the jack J to complete the connection to substation B.

As pointed out above, Figs. 4i and 5 taken together show a complete register sender. Specifically, Fig. 4 shows the control relays lO1-4:06 and the input-control sequence switch SF. The sequence switch SE distributes the series of impulses to the operating magnets of the registers shown in Fig. 5 and brings about a switching operation after all the digits have been received. Fig. 5 shows, in addition to the registers, the sender S which retransmits impulses in accordance with the setting of the registers.

In addition to the equipment mentioned in connection with Fig. 4, the distributor is shown in the lower lett-hand corner ot' the sheet. 4This distributor is common to a nurnber of finders such as the finder F, Fig. l,

maaar@ and it is used mainly to reduce the number oi relays necessary to be used individual to each of the finders.

Fig. 6 shows two re ister sets, Nos. l and 2, for controlling the isplay of numbers on the common lamp bank. Only one register set is shown in full. Fach set is provided with a finder switch, as shown, to connect it with an idle cord circuit, such as the cord circuit CC, Fig. 3.

it may be pointed out at this time that the trunk lines such as the one comprising con ductors 107-109, Fig. l, extending to the repeaters such as R are normally made artiticially busy and a trunk line is selectable only after it has been preselected by the finder such as F. lin order for this arrangement to be used most advantageously, it is preferable that a separate group of finders be provided for each group of selectors such as the group l including the selector 0S. By way of ez;- ainple, it has been assumed that the selector OS is capable of taking twenty rotary steps and has access therefore to twenty trunkspn any level. That being the case, the finder F has access to the same twenty trunks, the same being true of the other inders in the same group as the finder F. Other oiiice selectors are formed into another group and twenty trunks are brought out` from this group of otiice selectors. A separate group ot finders is assigned to this second trunk group, a distributor such as the one shown in Fig. lbeingl provided for this second finder group. ln this way, as many groups of trunks as are necessary may be provided to handle the trailic to any given manual oce. lit is assumed for convenience that the secondary switch SS, Fig. 2, (one of which is individuai to each repeater) is arranged so that it may select any one of fifty trunks. lt is assumed further that a group of fifty trunks is sufriciently large to handle the traflic from the automatic oiiice in question to the manual oice. lt more trunks than fifty are needed,

a switch capable of selecting more than fifty trunks may be provided instead of the secondary switch SS.

The invention having been described generally, a detailed description of the operation ot the apparatus shown will now be given. For this purpose it will be assumed that the subscriber at substation A desires to converse with the subscriber at substation B. It will be assumed for convenience that the number of the subscriber at substation B is 5-2986, the digit 5 being the office designation, 2986 being the line number.

When the receiver is removed at substation A, the line switch LS responds to the closure of a circuit over the line of substation A and selects an idle ofiice selector (selector OS, for example) in the usual manner by advancing its wipers 101-103 into engagement with an idle trunk .line leading to such oice selector. When the subscriber at substation A dials the olice digit 5 in the desired number, the ofiiceV selector OS raisesits wipers 1041-106 oppositie the fifth level of bank contacts and rotates them in Search of an idle trunk lille.

At this point the description of the progress of the call will be temporarily dropped and the description of the manner in which the repeater R is preselected and made available for use will be taken up. Referring to the distributor shown in Fig. 4, and assuming that the bank contacts on which its test wiper 420 is standing has been grounded due to the completion of the operation of the associated finder, a circuit is closed thru wi er 420 for relay 422. When this happens, re ay 422 operates and opens the circuit of relay 421, whereupon relay 421 falls backand among other thin s connects ma net 423 to test wiper 420. agnet 423 being self-interrupting, operates in a buzzer-like manner to advance the wipers 417-420 step by step until test wiper 420 finds an ungrounded test contact, for example the one associated with the register set shown. When this occurs, stepping magnet 423 ceases to operate, and relay 422 falls back and closes a circuit for relay 421. Relay 421 operates and disconnects stepping magnet 423. At its inner upper armature, relay 421 places ground on conductor 419, thereby closing a circuit thru test relay 401 and the operating magnet 120 of the inder F, Fig. 1, in series. At the same time, relay 421, at its lower armature, connects wiper 417 to wiper 418 thereby connecting the junction of test relay 401 and step ing magnet 120 as represented by wiper 41 to the test wiper 121 of the finder F, as represented by wlper '418. If the repeater on which the finder F is standing is idle, the connecting up of test wiper 121 is without any particular eiect and test relay 401, Fig. 4, operates right away However, if the repeater ,on which the finder is standin is busy or has been preselected by another nder, the test wiper 121 of the finder-F is encountering a ground potential on the bank contact on which it is standing, thereby shunting test relay 401, Fig. 4,'and preventing its energization. The ground potential on test wiper-121 is available for operating the stepping magnet 120 in the usual buzzer-like manner. Due to the action of operating magnet 120 the wipers 121-124 are advanced Astep by step unt-il test wiper 121 encounters an ungrounded contact. Assuming that the irst ungrounded contact is encountered by test wiper 121 when the wipers land on the set of bank contacts associated with the repeater R, the operation of test relay 401 in series with magnet 120, when this contact set is reached, results in the seizure of the repeater R. It' may be pointed out that magnet 120 does not operate in series with test relay 401.' Upon `operating, relay 401 preterminal; at its lower armature, it grounds the test conductor in the bank of test wiper 420 of the distributor; and at its lower armature it removes ground from the release conductor 411 and applies ground to the interrupter-start conductor 414.

In the repeater R, as a result of the ground- I ing of the test wiper 121 of the nder F by the inner upper armature of test relay 401, Fig. 4, relay 114 operates thru the middle lower armature of relay 115 and places ground on release trunk conductor 118 thereby closing a lookin circuit vfor itself and supplying groun thru test wi r 121 to hold test relay 401, Fi 4, operate after the distributor has been a vanced. As a further result of the operation of rela 114, ground is removed from release trun conductor 108 of therepeater R, thereby rendering the repeater R selectable to the eilce selector OS and the others having access to it.

In the distributor, Fig. 4, when relay 422 operates as a result of the closure of its circuit by test relay 401 thru wiper 420, it opens the circuit of the associated slow acting relay 421 with the result that relay 421 falls back after a slight interval and opens the connection to wipers 417-419, at the same time connecting up operating magnet 423. Magnet 423 operates in the usual buzzer like manner to advance the distributor to another idle finder, whereu on the distributor stops and starts said iin er in the manner above described. s

As a result of the grounding of the interrupter start conductor 414 at the lower armature of test relay 401, impulse relay 505, Fig. 5, commences to operate and restore under the control of the interrupter I. It will be noted, however, that the operating magnet 504 of the sender S does not respond at this time owing to 'the fact that conductor 413 is not yet grounded.

Returning now to the description of the. progress of the call, it will be assumed that the otlce selector OS seizes the preselected trunk line comprisin conductors 107-109 leading to the repeater when it rotates, after having been operated to the fifth level as hertofore described. When the repeater R is seized, line relay 111 operates thru contacts of the electro-polarized relay 110, over conductors 107 and 109, and over the calling line, and closes a circuit at its inner armature for release relay 112, at the same time openingat its lower armature a point in the impulse circuit to be subsequently traced and preparing a circuit for switching relay 115.4 Release relay 112 operates .and places a multiple ground ICI) llO

connection on release trunk conductor 118 at the impulse conductor 125 thru contacts of release relay 112. Each time conductor 125 is grounded a circuit is closed thru wiper 124 of the finder F, upper armature of relay 401, Fig. 4, series relay 403 and the upper wiper of the sequence switch SE, in its first position,

`for the operating magnet of the thousands register, Fig. 5. The operating magnet of the thousands register responds to these two impulses and advances the associated wiper two steps. The slow acting series relay 113, Fig. 1, is energized throughout the series of impulses from the impulse conductor 125, but its operation is of no particular utility at this time. i. l

Series relay 403, Fig. 4, operates in response to the first impulse delivered to the operating magnet of the thousands register, and, being slow acting, remains operated throughout the digit. Upon operating; relay 403 closes a circuit for the auxiliary slowacting relay 404, whereupon relay 404 oper-l ates and prepares a circult for the operating magnet of the sequence switch SE.

When series relay 403 falls back at the end of the digit, it opens the circuit of auxiliary relay 404, and relay 404 falls back after a slight interval. During the time required for relay 404 to fall back after its circuit is opened a circuit is closed for the operating magnet of the sequence switch SE thru contacts of relays 403 and 404. The sequence switch SE, therefore, advances its wi ers one step, shifting the impulse conductor rom the operating magnet of the thousands register to the operating magnet on the hundreds register.

When the hundreds digit 9 is dialled, the operating magnet of the hundreds register responds by advancing the associated wipers step-by-step to the ninthbank contact; the operating magnet of thetens register responds to the tens digit 8 and sets the associated wiper; and the operating magnet of the units register responds to the units digit l6 and sets the associated wiper on the sixth bank contact. It will be understood of course that this progressive operation is brought about by the above described advance of the sequence switch SE at the end of each digit.

When the wipers of the sequence switch SE advance onto the fifth bank-contact set at the end of the units digit, ground Iisencountered by the lower wiper of the sequence switch while the auxiliary relay 404 is still energized, closing a circuit thru contacts of relay 404, contacts of relay 401, wiper 123 of the finder F, upper contacts of relay 115 ofthe repeater R, conductor 117 and contacts of switching relay 202 of the secondary switch SS, for line relay 201. Line relay 201 responds and locks itself to the grounded release trunk conductor 118, grounded at this time at the lower contacts of release relay 112 0f the re eater R. A moment later, the auxiliary re ay 404 falls back and opens the initial circuit of the line relay of the secondary switch SS, leaving this relay locked to conductor 118.

As a result of the operation of the line relay of the secondary switch SS, a circuit is closed at the inner lower contacts of the relay for switching relay 202 and operating magnet 203 in series. At the lower contacts of relay 202, test wiper 205 is connected to the junction of the associated vswitching relay and operating magnet. rllhe result is that the operating magnet operates thru the test wiper and the switching relay 202 is maintained short circuited until wiper 205 is advanced to an ungrounded bank contact.

At this point the description of the call will again be momentarily halted while a description is given of the manner in which the registers in the manual oce operate to preselect and render available the interoce trunks.

Referring now to Fig. 6, it will be noted that two registers are provided, register No. 1 and register No. 2. Register No. 1 is shown in full and it has associated therewith a {inder having wipers 601-606. Assuming now that the finder is advanced in a manner to be subsequently explained from the bank contact set on which it is standing' to the set associated with line TL, the said trunk line TL is seized upon the operation of test relay 608 when the wipers 601-605 come to rest on the contacts in the trunk line. Relay 608 energizes through the lower contacts ol relay 609 and through the operating magnet. At its lower contacts relayl 608 connects line relays 610 and 611 to the corresponding wipers 602 and 601; at its inner upper armature it disconnects the auxiliary test wiper 606; and at its inner lower armature it locks.

itself energized independent of the inner lower armature oit relay 612.

As a result of the line relays 610 and 611 being connected up at the contacts of relay 608, relay 212, Fig. 2, energizes thru wipers 601 and 602, conductors 321 and 822, contacts of relay 301, conductors 212 and 213, and contacts of relay 210. rlhe line relays 611, 610 and 611, are not operated at this time owing to the relatively 'high resistance of relay 211.

When relay 211 operates it disconnects ground from test con uctor 208 and prepares a circuit for relay 210.

Returning now to the description of the progress of the connection, it will be assumed that the trunk line TL is the first available one found when the secondary switch SS operates in search of an available trunk line. That being the case, wipers 204--206 stop in engagement with the contacts to which conductors 207-209 are connected. The switching relay 202 operates in the usual manner when this trunk line is reached, extending the conductors 117 and 119 tothe corresponding conductors 207 and 209. At its inner lower armature, relay 202 opens a point vin the test circuit` and places ground on test wiper 205, whereupon relay 210 operates over conductor 208 and contacts of relays 208-210 and locks itself to lthe said conductor. At its upper and lower armatures, relay 210 disconnects conductors 212 and 213 from relay 211 and connects them to conductors 207 and 209. Relay 211now falls back and prepares to ground conductor 208 again.

The conductors 212 and 213 to vwhich the line relays 611 and 610, Fig.6, are connected are now extended thru conductors 207 and 209, wipers 204 and 206, contacts of relay l202, conductors 117 and 119 resting contacts ofrelay 115, wipers 122 and 123, contacts of relay 401, Fi 4, contacts of relay 404, and contacts of re ay 406 to the start-control relay 405. Relay 405 operates in series with the line relays of register No. 1, Fig. 6, but the said line relays do not operate due to the rel-l atively high resistance of relay 405. Relay 405 closes a circuit for start rela 406, whereupon relay 406 operates and lloc s itself thru contacts of the switch-thru relay 402. Relay 406 also disconnects the negative and positive trunk-conductor extensions from the startcontrol relay 405 and extends them over conductors 415 and 416 to the closed loop in- V cluding contacts of the sending relays 506 and 508. When this takes place, relays 610 and 611, Fig. 6, energize in series an each closes a circuit for release relay 612. Release relay 612 operates and prepares circuits for the operating magnets of the thousands and tens registers, respectively.

As a further result of the operation of start relay 406, Fig. 4,` a multiple ground connection is made at its lower contacts to the test conductor extending to a contact in the bank of wiper 420 of the distributor; a multiple connection is made to the interrupter start conductor 414 at another lower armature of relay 406; and, at still another lower armature of relay 406, ground is placed on conductor 413 thru contacts ofrelay 402, whereu on the operating magnet 504 of the sender commences to energlze and deenergze under the control of the impulse rela 505, which relay it will be remembered 1s loperatin under the control of the interru ter from the grounded conductor 414.

Upon each energization of the operating magnet 504 the usual pawl and ratchet arrangement (not shown) operates pre aratory to advancing the wipers upon eac energization of the ma net. When the operating magnet deenergizes the first time, as it does upon the next energizationof impulse relay 505, wiper 501 encounters its second bank contact and thereby grounds conductorl 510. As a result, each succeeding deenergization of relay 505 results in the closure of a circuit for sending relays 506 and 508 at the same time that a circuit is closed forthe oiperating magnet 504. It will be noted that t e circuit of sending relay 506 includes the upper winding and upper contacts of stop relay 507 and that the circuit ofsendingrelay 508 includes the upper contacts and the upper Winding of stop re ay 509. The marginally adjusted stop relays do not operate in series with the sending relays.

According to the revious assum thousands di 't is t e digit 2 an digit is the contact in the ank of the thousands register. is grounded and the eighth contact in the bank of the tens register is grounded. There the tens is therefore no intererence b y the registers with the operation of the sendin relays until two steps of the sending switc have been completed following the first step when the sending rela s 506 and 508 start to operate. .Each time t e sending relays both operate conductors 415 and 416 are both disconnected yand left open, whereupon bothline relays 610 and 611, Fig. 6, fall back. Then when sending relays 506 and 508 restore upon the energization of impulse relay 505, when the advance of the wipers 501--503 takes place, the line relays 610 and 611, Fig. 6, are con-4 nected in series again and they again operate. 'This operation is repeated upon the following step of the wipers of the sender, sending the second impulse to both line relays. When the second impulse to the line relays is terminated, the wipers 501--503 land upon the fourth set of bank contacts, whereupon the ground potential placed on the second contact in its bank by the wi er of the thousands register is encounter by wiper 502, whereupon the sending relay 506 is deprived of batte potential and a stop relay 507 is energize thru its upper winding. Relay 507 locks itself to the grounded conductor 510 and disconnects sending relay 506. The result is that sending relay 506 remains normal during further advance of the sender S and the sending relay 508 operates alone.

Each time relay 508 operates alone, it grounds the negative conductor 516 thru the resistance R and thru contacts of sending relay 506 so as to hold the negative line relay 611, Fig. 6, operated, and it disconnects the tion,

i it 8. As a result the second i lee I positive conductor 416, thereby deener izing the positive line relay 610, F ig. 6. Eac time sending relay 508 restores 1t connects the two line relays in series again, whereupon relay 610 reoperates. In this way, the two relays are enerfrized in series over a metallic loop as beforebut a high resistance holding circuit is maintained for one of them while the impulses are being delivered to the other. Therefore, the good e'ects of a loop impulsing circuit are retained while effective impulses are actually transmitted over only one conductor.

At the end of the eighth impulse transmitted to the positive line relay 611, Fig. 6, wiper 503 encounters the bank contact connected with the one grounded by the tens register in its eighth position, closing a circuit or the upper winding of stop relay 509. `When this circuit is closed sending relay 508 is short circuited immediately so as to prevent further operation of relay 508, and stop relay 509 operates, locking itself to conductor 510 at its lower armature and disconnecting relay 508 at its upper armature.

The wipers of the sender S continue to advance and nothing more happens until wiper 501 passes o the eleventh bank contact and engages the disconnected twelfth contact. When this occurs, conductor 510 is ungrounded and relays 507 and 509 fall back andagain connect up sending relays 50` and 508. Relays 506 and 508 cannot respond during the next two steps of the sender on account of the absence of a ground potential on conductor 510. This interval is .provideddn order to afford a spacing between series of impulses so as to allow the slow acting change-over relays in the registers in the manual office to fall back and perform change-over operations in a manner to be pointed out subsequently.

When the wipers 501- 503 of the sender S arrive on the fourteenth contact set, wiper 501 grounds conductor 510 again. As a result, the sending relays 506 and 508 are operated again upon each succeeding deenergization of impulse relay 505, sending impulses over both conductors 415 and 416 to the line relays 611 and 610, Fig. 6. The sending operation continues um'nterruptedly until wiper 503 encounters a contact grounded by the wiper of the units register after the sixth units impulses have been transmitted by sending relay 508. When this grounded contact is encountered, stop relay 509 operates and locks itself to the grounded conductor 510, at the same time disconnecting sending relay 508. As a result, relay 508 ceases to operate and the negative sending relay 506 continues to operate until the digit 9 has been transmitted over the negative conductor 415, whereupon stop relay 507 is energized thru wiper 502 of the sender and the wiper of the hundreds register in series. When thisY occurs relay. 507 locks itself to conductor 510 and disconnects relay 506.

'llhe advance of the wipers of the sender continues until wiper 501 passes 0E the 24th banlr .contact and lands on the 25th bank conn tor 412. As a result, the operating magnet- 504 derives current from conductor 412 thru the 25th bank contact of wiper 501 and ad-y vances the wipers another step into the normal position shown in the drawings. Vlhen this occurs the circuit of switch-thru relay 402 is opened, but this relay being slow acting, remains operated for an interval. its a further result of its operation, switch-thru relay 402 at its middle lower armature unlocks start relay 406 and places a multiplel ground on the interrupter start conductor' 414 so as to maintain rthe impulsing operation of relay 505 for the time bein'g. Switchthru relay 402 also places a ground on the impulse conductor extending to the impulse wiper 124 of the finder F, with a result to be subsequently mentioned. Relay 402 also opens the circuit of test relay 401, whereupon relay 401 falls back and replaces the ground potential on release conductor 411, thereby operating the release-magnet 408 of the sequence switch SE thru the associated onormal contacts, and operating the release magnets of the thousands,. hundreds, tens and units registers, respectively, Fig. 5. By the operation of these release magnets the sequence switch and the registers are restored to their normal position and the release magnet circuits are opened by the respective o-normal contacts. After an interval, switch thru relay 402 falls back and removes ground from the impulse wiper 124 of the finder F at its upper armature, and it removes ground from impulse conductor 414 at its middle lower armature, whereupon the impulse relay 505, Fig. 5, ceases to operate and start relay 406 falls back and ungrounds the conductor extending to the bank of test wiper 420 of the distributor. rlhe register sender is now selectable by the distributor and may be taken for use lto handle another call.

Responsive to the placing of ground on the impulse wiper 124 of the finder F, as mentioned above, a circuit is closed thru contacts of release relay 112 and the lower armature, operated, of line relay 111 for the switching relay 115 of the repeater R. Relay 113 isopics iis

ifo

'ist

fate'dat'th-is time, but'its operation is merelyincidental'ff Relay 115 at its mifiddle lower armaturedisconnects relay 114, as it is no longer necessary vtomaintain this rela energized;-` it-llocks itself to the grounds conductor 118 and opens its initial circuit at its inner lower armatureg-and at its upper 'and lower armatures it disconnects the trunk conductors 117 and 1 19 from the bank contacts of the-finder F and connects them instead to the talking conductors associated with thevcondensers above and below the electrolarized relay 110. Atl the same time, a ridgeis closed at the upper and lower armatures of rela 115 across conductors 117 and 119' inclu ing the lower winding vof the electropolarized relay 110 and .impedance 126. When this bridgeis closed, the line relays 610 and 611,Fig. 6,'which have been restored w following' the .deenergization of test relay 401,

Fig; 4, reoperate, but the electropolarized relay 110 is not operated due to thecontrary direction of the "current flow in its lower winding.

Nori, Fig. 6, of the transmitted impulses, each time the negative line relay 611 falls back inresponse to-one ofthe two interruptions produced in its circuit representative of thethousands digit 2 it closes a circuit for the operating magnet of the associated thousands register, the circuitat the time ofits rst closure including the armature of relay 611, normal, inner upper armature of release relay 612, operated, normally-closed oit-normal contactsofthe thousands register, andA the series relay 614. By the o ration of the operating magnet, the wiper o the thousands register is advanced onto the second associated bank contact, thereby preparing a circuit for the No. 2 thousands lamp. Series relay 614 operates and remains operated throughout the digit, being slow acting. Relay 614 prepares a new d impulsing circuit which becomes effective upon the shifting of the associated off normal contacts.

At the end of the thousands digit 2, series relay 614 restores and shifts the associated' operating circuit from the operating magnet of the thousands register to the operating magnet of the hundreds register.

When relay 611 responds to the hundreds digit 9, nine impulses of current are delivered thru the o normal contacts of the thousands register TH and thru the contacts of series relay 614 to the operating magnet of the hundreds register through the associated series relay. The series relay of the hundreds register operates in response to the first series l of impulses and remains operated throughout the digit. At its inner armature, the series net until the end of the digit.- At the end vlished b over a circuit path similar to the one over which the impulses are transmitted to the operating magnet of the thousands register. This circuit path includes the-resting contacts of relay 610 and operated contacts of release relay 612. By the combined action of lthe olf normal contacts of the tens register and of the associated series relay, the impulsev circuit is transferred from the tens register tothe units register at the end of thetens hen the units digit 6 `is delivered coiny l cident with the delivery o f the hundreds digit Considering now the receipt, by the register 9, six impulses of current are delivered thru the series relay to the operating magnet of the units register, with the result that the wiper of the unit register is set on the sixth bank Contact. By the joint action of the series relay of the units-register and of the associated off-normal contacts the operating circuit is maintained intact until the end of the'units digit, whereupon it is opened bythe series relay.

' With the hundreds registei` andthe units register both in an operated condition with their onormal contacts closed and with both of their series relays deenergized, a vcircuit v.for the display relay 613 exists, "being-estab whichever series relay falls back A last. T is circuit includes the oit-normal contacts and series relay contacts of the hundreds and units registers,'lower contacts of relay 612, and contacts ofthe display relay 613 of the register'No. 2 and the display revlay 613. When this circuit is closed,- display relay 613 operates and opens la point in the fcircuitofiisplay relay 613. This interlocking arrangement between the two display relays 'is necessary to prevent a double display. AThe result of this arrangement is that if two displays are ready at the vSametime the first display relay to operate. revents the operation of the other until'the rst'number has been disposed'of andthe successful display relay has fallen back. lll'pon the closure of the circuitthru display relay 613, this re lay operates land grounds the wipers of the registers at its lower armatures, thereby causing the lamps on which the wipers of the registers are standing to become lighted and dis-- play the number 2986.

In order that the operatormay know which cord circuit to use 'to 'complete the connection a circuit is closed at the upper armature ot i display relay 613 and thru wiper 604e and fis conductor 324 for the assign relay 305 of the cord circuit CCy on which the wipers of the finder associated with register No. 1 are standing. Assi relay 305 operates and prepares a bus -bac circuit at its lower armature, and it ligiits the assign lamp 308 at its upper armature.

Upon noting the lighted condition of the assign lamp 308, the operator picks up the plug P of the cord circuit CC and makes the usual tip busy test on the sleeve of the jack J. Assumin first that the jack J tests busy, the

operator ears the busy click over the tip ofthe plug and thru her test circuit. The operator then merely replaces the plug in its normal position and operates the busy key 310, common to her position. At this'time, only one assign relay, the assign relay 305, can be operated. As a result, relay 301 operates through contacts of relay 305 and switches the conductors 212 and 213 from in connection with conductors 321 and 322 and extends them instead to the left-hand repeatingcoil windings. As a result line relay 302 operates and closes a multiple circuit for relay 301. At the saine time, relay 301 places ground on conductor 323 so as to cause a further advance of the finder associated with register No. 1 in a manner to be hereinafter explained. Relay 302 also connects the busytone lead to the upper right-hand repeatingcoil terminal thru the associated small condenser and contacts of sleeve relay 307. rllhis busy tone is heard by the calling subscriber who replaces his receiver and brings about the release of the connection in a manner to be subsequently described.

Assuming now that the jackA J tests idle, the operator inserts the plug l? therein, whereupon sleeve relay 307 energizes over the sleeve of the plug and jack and thru the usual cuto relay of the called line. At its inner upperarmature, relay 307 opens a point in the busy Vtone circuit and it closes momentarily a circuit for the disconnect lamp 309 at its inner lower armature. Relay 307 also disconnects the tip conductor from the operators test circuit and connects the tip conductors to ground through the upper right-hand repeating-coil winding and contacts'of relay 304, and connects `the ring conductor to the ringing circuit thru contacts of the ring-cutoff relay 306. Ringing current from the ringing interrupter is now sent out thru the lower winding or' the ring-cuto1 relay and thru ,the ring conductor to the called substation,

`returning to ground over the tip conductor.

Since the -upper right-hand repeating coil .winding is included in the return path of the ringing current, a ringing tone is induced in the left-hand windings and is heard by the calling subscriber.

As a result of the closure of they circuit of relay 301, the conductors 212 and 213 are a multiple circuit for relay 301 so that it is now maintained operated from two sources.

As a further result of the operation of relay 301, conductor 323 is grounded, whereupon the operating magnet of the finder associated with register No. l is operated thru wiper 603, and test relay 608, being short circuited restores. Relays 610 and 611, Fig. 6, fall back as a result of the switching over of conductors 212 and 213`by relay 301, Fig. 3. Test relay 608 opens a point in its locking circuit, and, therefore, it cannot again reoperate, regard less of how far t-he wipers 601-606 advance until release relay 612 falls back responsive to the deenergization of relays 610 and 611. When relay 612 falls back, it connects up relay 608 again at its lower armature, and closes at its inner upper armature a circuit through the low-resistance lower winding of relay 609,

including the upper armature of relay 611, a

for the release magnets of the register. This circuit includes the od normal contacts of the several registers. As a result of the closure of this circuit the registers are restored to normal position in the usual manner. As further result of the deenergization of relay 612 the circuit of the display lamp 613 is opened immediately so that this relay falls back and extinguishes the lighted lamps and closes a point in the circuit of display relay 613 of the register No. 2. Since the circuit of the release magnets includes the lower winding of the guard relay 609, relay 609 operates' when the release magnet circuit is closed and it again disconnects test relay 608 so as to prevent it from energizing during the releasing operation. Relay 609 also disconnects the test wiper 603 from the test cir cuit so as to prevent operation of the finder while the registers are releasing.

When the releasing operation is completed and all of the o normal contacts have opened, relay 609 fallsbaclr and permits the t'ssociated finder to preselect another trunk Returning now to the established connection, when the called subscriber responds to the ringing of his bell by the ringing current sent out thru the plug P of the cord circuit CC, ring-cut-o relay 306, which relay does not respond to the ringing current due to the condenser included in series wit-h the ringer at the called substation, responds to the flow of current from the exchange battery thru the ringing interrupter and over the called line. Upon responding, relay 306 removes the shunt from around its upper winding, thereby locking itself energized in series with sleeve 4relay 307; and at its upper and lower l me Mii

armature it opens the ringing circuit and completes the talking circuit.

-T e battery-feed relay 304 now operates 'over the called line and removes the shunt v versal as regards the connection between conductors 107 and 109 and the windings of line relay 111. This latter reversal may be used whenever desired for the operation of meters or the like, or for giving supervision when the call is from an operators switchboard at a private branch exchange, or for any other desired purpose.

The two subscribers may now converse with each other in the usual manner.

When the conversation is terminated, the two subscribers replace their receivers.

When the receiver is replaced at the substation B, battery-feed relay 304 falls back whereupon relay 303 is restored and reverses the connection between line relay 302 and the repeating coil windings back to normal. When this occurs, the electro-polarized rela 110, Fig. 1, restores and reverses the associated connect-ions to normal.

When the receiver is replaced at substation A, line relay 111 of the repeater R falls back and opens the circuit of release relay 112, at the same time closing at its lower contacts a circuit thru contacts of relay 112 for relay 113. Relay 113 responds and opens a point in the guarding circuit of the repeater so as to enable the line switch LS and the ol`n`ce selector OS to release. A moment later, release relay 112 falls back and removes ground at its lower armature from release trunk conductor 118; opens the circuit of the slow acting relay 113 at its inner lower armature; and at its upper armature it removes ground from conductor 108 and prepares a circuit for replacing ground on conductor 108 when relay 113 falls back. When the ground potential is removed from conductor 108 the line switch LS and the oilice selector OS both release in the usual manner. A moment later relay 113 falls back and replaces'the ground potential on conductor 108 so as to guard the repeater R from seizure by an oiiice selector such as OS until the repeater R has been again preselected by a finder such as F. This preselection is now possible owing to the fact that the ground potential has been removed from release trunk conductor 118, a branch of which forms the test conductor in the bank of test wiper 121 of the finder F.

Responsive. to the removall of the ground potential from release trunk conductor 118 by release relay 112 of the repeater R, line relay 201 of the secondaryswitch SS falls back and opens a further point in its locking circuit at its upper armature; it opens a further point in the test circuit of the line switch at its lower armature; and at its, inner lower armature it opens the circuit of switching relay 202, whereupon relay 202 falls bac restoring the circuit conditions of the switch to normal. As a result of the disconnection of the ground potential from test wiper 205 by the switching relay 202, relay 210 of the trunk circuit TC, which has been energized previously over release trunk conductor 208, falls back and opens the circuit of the slow-acting relay 211 at its inner lower armature; closes a temporary guarding circuit through contacts controlled by its inner lower armature and the upper armature', operated, of relay 211: and at its upper and lower armatures it reconnects the high resistance relay 212 across the conductors of the trunk line TL. Relay 212 now operates and closes a locking circuit for the slow-acting relay 211 before the said relay has had time to fall back. Relay 211, therefore maintains the temporary guarding circuit closed as long as relay 212 remains operated.

Regarding the bringing in of the disconnect signal at the cord circuit CC, it may be pointed out that switching relay 115 of the repeater R, Fig. 1, falls back when the ground potential is removed from conductor 118 and it removes the bridge from across'conductors 117 and 119, whereu on the line relay 302 of the cord circuit CCI, Fig. 3, falls back and lights the disconnect lamp 309 thru contacts of sleeve relay 307. Due to the high resistance of relay 212, line relay 302 remains nonoperated when relay 212 reoperates over the trunk line TL in series with line relay 302, as above pointed out.

When-the operator notes the lighted condition of the disconnect lamp 309Vand removes the plug P from the jack J, relays 306 and 307 fall back. Relay 307 opens the circuit of the disconnect lamp 309 and it also opens the circuit of relay 301, whereupon relay 301 falls back and disconnects the ground potential from test conductor 323 so as to render the cord circuit selectable to the associated finders. Relay 301 also disconnects the conductors 212 and 213 from the associated repeating coil windings. When this occurs, relay 212 in the trunk circuit TC, Fig. 2, falls back and opens the circuit of relay 211, at the same time preparing a new guard circuit for the trunk line. A moment later, relay 211 falls back and transfers conductor 208 from ground at its own contact to ground thru contacts of relay 212. In this way, the trunk line TL is guarded until it is again preselected in the manual oiice.

The entire connection is now released and the apparatus involved therein may be used in setting up subsequent connections. When all cords are busy, all relays such as 301 are operated. Direct ground potential is then removed at all points from the common conductor 326, whereupon current through resistance 325 operates relay 609, Fig. 6, (and the similar relay in the other register set) provided the register set is not operating, in which case relays 610 and 612 are normal. Relay 609 prevents useless operation of' the associated finder.

I claim:

l. In a telephone system, automatic trunkselecting mechanism, trunk lines accessible thereto, cach of said trunk lines being normally non-selectable to said switching mechanism, a plurality of digit registers, register connecting mechanism for connecting vsaid registers to idle ones of said trunk lines, and means responsive to the connection of a register to a trunk line for rendering such trunk line selectable to said trunk selecting mechamsm.

2. In a telephone system, automatic trunk selecting mechanism, trunk lines accessible thereto, each of said trunk lines being normally non-selectable to said mechanism, a plurality of digit registers, register connecting mechanism for connecting said registers to idle ones of said trunk lines, means responsive to the connection of a register to a trunk line for rendering such trunk line selectable to said trunk selecting mechanism, and distributing mechanism common to all said registers for governing the operation of said register connecting mechanisms so that such mechanism maintains each idle register connected with an idle trunk line.

3. In a telephone system, a plurality of groups of switching mechanism, a like plurality of groups of trunk lines accessible respectively to said groups, registers divided into as many groups as there are grou s of -said trunk lines, each of said trunk lines eing normally non-selectable to the said switching mechanism having access to it, a trunk finder connected to each of said registers for finding and connecting the register with an idle trunk line, multiple connections between the banks of the said finders such that the finders corresponding to a given group of registers having access to trunk lines in the corresponding trunk group only, and means responsive to the effecting of a connection between a idle trunk line and a register sender by the finder associated with such re ister sender for rendering the connected trun line selectable to the group of switching mechanism having access to said trunk line.

4. In a telephone system, an automatic office, a manual office, a group of trunk lines extending from said automatic office to said manual office, switching mechanism in said manual office for completing to manual lines terminating therein connections extending from the automatic office to the manual office over said trunk line, call-indicating equipment including registers in said manual office for indicating to the manual operator the desired numbers, preselecting switching mechanism for effecting connections between said registers and idle ones of said trunk lines and for setting up a current-flow over each connected trunk line, automatic switching mechanism in the automatic office having access to said group of trunk lines, and means in said automatic office responsive to the current flow over a trunk line resulting from the connection of the register in the manual office thereto for rendering such trunk line selectable to said switching mechanism in the automatic office.

5. In a telephone system, an automatic office, a manual office, trunk lines extending from said automatic office to said manual office, call indicating equipment in the manual office for indicating to the operator thercat the destination of calls received over said trunk line, register senders in the automatic office for controlling the operation of said call indicating equipment, a group of local trunk lines in said automatic office corresponding to said manual office, automatic switching mechanism in said automatic office responsive to the portion of a number indicative of said manual office for extending a connection to one of said local trunk lines, means responsive to the remaining portion of the number for operating one of said register senders to record such remaining portion, secondary switching apparatus, and means effective only after the said remaining portion of a number has been completely registered for operating said secondary trunking apparatus to effect a connection between the seized local trunk line and an idle one of said automatic to manual trunk lines.l

6. In a telephone system, a register sender, means for extending a connection thereto and for registering a plurality of digits in a tele phone number, a distant register, means for extending a connection from said register sender to said distant register, said connection including two conductors, and means in said register sender for transmitting simultaneously to said distant register, two digits of equal length by transmitting impulses over said two conductors in series.

7. In a telephone system, a register sender, means for extending a connection thereto and for registering a plurality of digits in a telephone number, means for extending a connection from said register sender to a distant register, said connection including two conductors, means in said register sender for transmitting simultaneously to said distant registers, two digits of equal length by transi mitting impulses over said two conductors in series, and means effective when the two digits are ofunequal length for transmitting the lil) extra portion of the longer digit over one conductor of the,trunk line while effective i impulses over thiJ other conductor are prevented by a holding circuit including a. separate return.

8. In combination, a sender and a distant register, two conductors extending from said sender to said. register, a separate grounded receiving device in said register in series with each of said conductors, said conductors being conducted in series in said sender, a source of potential in series with said conductors for maintaining said receiving devices normally energized, and means for transmitting simultaneously impulses representing two digits over both conductors in series by interrupting said series circuit in said sender, and means effective when the two digits'are of unequal length for establishing upon each interruption a holding circuit over either of said conductors including a separate return for maintaining operated one of said repeating devices while the other is responding to the interruption.

9. In a telephone system, two otlices, a trunk line extending from the first otlice to the second ofiice, automatic switching mechanism in the first office having access to said trunk line, switching mechanism in the second office for completing a connection extended to said trunk line by said switching mechanism in the first oliice, means for releasing the connection in the first oilice prior to the release of the switching mechanism in the second oiiice, and means in the first oice, controlled over the two conductors of said trunk line in series and effective as long as the connection remains intact with the sec'- ond office for rendering and maintaining said trunk line busy to the switching mechanism in the first oice. l

10. In a telephone system, an automatic office and a manual oiiice, a trunk line ex` tending from said automatic oiiice to said manual cfce, automatic switching mechanism in said automatic otlice for extending a connection to said trunk line, operator controlled mechanism in the manual oice for extending a connection from said trunk line, means for interrupting the connection to the trunk line in the automatic oflice and for giving the operator in the manual oice a disconnect signal, and means in the automatic otiice responsive to the interruption of the connection in the automatic olice and responsive to current flow over the two talking conductors of said trunk line in series for placing a guarding potential on said trunk line in the automatic oiice to prevent reseizure of said trunk line bythe automatic switching mechanism, and means responsive to the breaking down of the connection in the manual oiice under the control of the operator for causing said means in the automatic oiiice` to remove said guarding potential.

11. In a multi-cnice telephone system, a'

trunk selecting mechanism, an inter-oilice trunk line accessible but nonselectable at 'one end to said mechanism, means for extending a connection from the other end of said trunk line and for setting up a current flow over the trunk line, and means for thereupon rendeling said trunk line selectable to said trunk selectlng mechanism responsive to said current-flow.

12; In a multi-cnice telephone system, an inter-oiiice trunk line, means at one end thereof for indicatin that the trunk `line is in a non-useable con ition, means for linking an extension to the other end of the said trunk line and for applying a potential to a talking conductor thereof, and means for thereupon removing the non-useable indication from the said one end of the trunk line responsive to said application of potential. y

13. n a multi-oiice telephone system wherein inter-oice trunk lines are maintained unselectable at one oiice when they are not connected to receiving apparatus at the other oiice, means effective upon the connecting of a trunk line to receiving apparatus for setting up a current-flow over said trunk line, and means responsive thereto for removing the unselectable condition.

. 14. In a telephone system wherein trunk lines are maintained artificially busy at one end when they are not connected to receiving apparatus at the other end, means responsive to current-low resultin from the connection of a trunk line to receivlng apparatus for removing the busy condition, and a circuit including a talking conductor of said trunk line for controllin said means.

15. In a te ephone system wherein trunk lines are indicated as unselectable at one end when they are not connected to receiving apparatus at the other end, means eiective upon the connection of a trunk line with receiving apparatus for removing the unselectable indication, and a circuit including the two talking conductors of said trunk line in series for controlling said means.

16. In a telephone system, a telephone line, a sending device at one end of said line, a receiving device at the other end of said line, and means for operating said sending device to send two digits simultaneously over said line to said receiving device.

17. In a telephone system, a telephone line, a sending device at one end of said line, a receiving device at the other end of said line, and means for operating said sending device to send simultaneously two digits of the sam telephone number over said line to said receivl ing device.

18. In a telephone system, a sending de vice, a receiving device, and means for operating said sending device in accordance with a telephone number to transmit two digits of such telephone number simultaneously to said receiving device.

19. In a tele hone system wherein impulses representing igits are transmitted incidental to the setting up ot telephone connections, means for transmitting a single series of impulses indicative of a given digit and for registering such digit and another digit in response thereto.

20. In a telephone system wherein impulses representing digits are transmitted incidental to the setting up of telephone connections, means for transmitting a 'series of impulses representing a digit of a given value and for registering such digit and a digit of a smaller value in response thereto.

21. In combination, means for transmitting a series of impulses, two registers, and means for operating one register to record one digit in response to such series and for operating another re ister simultaneously to record a digit of di erent value in response to such series.

22. In combination, two registers, means for generating a train of impulses, and means for setting one register responsive to only a predetermined portion of the impulses and for operating the other register in accordance with all of the impulses.

23. In a telephone system wherein impulses are transmitted incidental to the setting up of telephone connections, means for transmitting a series of impulses representing a digit of given value, two registers, means for operating one of them in response to said impulses to register the transmitted digit and for operating the other one to register a digit of smaller value, and means for changing the character of the transmitted impulses as soon as the digit of smaller value is registered.

24. In combination, an impulse transmitter, an impulse receiver, means for operating said transmitter to transmit a series of impulses, and a plurality of registering devices in said impulse receiver responsive to said series of impulses.

25. In combination, an impulse transmit-l ter, an impulse receiver, means for operating said impulse transmitter to transmit a group of impulses representing a digit and for transmitting a group of impulses representingan other digit, the second group being superimposed on the first said impulses so that all said impulses comprise a single series, and two registers in said receiving device responsive respectively to the said two groups of impulses.

26. In a transmitting and receiving system arranged to transmit and receive digits of numbers by means of impulses, two registers, an impulse circuit extending between the transmitter and receiver, and means for sending impulses over said impulse circuit from the transmitter to the receiver to operate both of said registers during the same period of time to register two digits of the same number.

27. In combination, an impulse receiver i11- cluding a plurality of pairs of registers arranged to register a plurality o' pairs of digits, respectively, a receiving circuit arranged to be associated with said pairs of registers successively, each of said pairs of registers being arranged and connected to operate from the receiving circuit to register a pair of digits, and means responsive to a pair of digits being received for transferring the association of the receiving circuit from the pair of registers with which it is associated to the next pair of registers.

28. In combination, two pairs of registers, a receiving circuit associated with the first pair, means responsive to impulses coming in over said receiving circuit for operating the first pair of registers, and means responsive to the cessation of'said impulses for transferring the receivin circuit from the first pair of registers to t e second pair of registers.

29. In combination, two pairs of registers and a receiving circuit, means responsive to impulses representing tWo digets received during the samefperiod of time for operating the first pair o registers to record a pair of digits, and means responsive to the cessation of the impulses representing the longer of the two digits for transferring the receiving circuit to t'he next pair of registers.

30. In combination, registering apparatus, a sender, a plurality of groups of responding devices, a set of actuating conductors, means for setting said registering apparatus, means for controlling said sender in accordance with the setting of said registering apparatus to exercise a control over a plurality of said conductors, means for operating one of said groups of responding devices in accordance with the control exercised and for thereupon transferring said 'conductors to the next group of responding devices.

31. In combination, a register sender, a pair of actuating conductors, a plurality of storage sets, means for operating the sending apparatus of saidregister sender in accordance with the setting of the registering apparatus thereof to exercise a control over said pair of actuating conductors, one of said storage sets being responsive to the control to register the control exercised, and means effective upon the cessation of the control exercised over said pair of conductors for disassociating the conductors from the first storage set and for associating them with the second storage set.

32. In combination, registering apparatus arranged to register characters, a pair of conductors, a sender arranged to operate under control of said registering apparatus to send an impulse over one of said conductors and to send an impulse over the other of said conductors simultaneously, a air of storage devices connected to said con uctors, respectively, another pair of storage devices, the rst pair of storage devices being responsive, respectively, to the impulses sent over said pair of conductors, and means effective upon the termination of the pair of impulses for thereupon transferrin the pair of conductors to the next pair o storage devices.

33. In combination, register-in apparatus operable to register a pair o diglts, a pair of receivin daevices, and a transmitter operable under t e control of said registering apparatus to transmit two groups of impulses simultaneously 'to said receivers representing the registered digits, respectively.

34. Incom ination, registering apparatus arranged to register a pair of digits, and a sender operable under the control of said registering apparatus to send two groups of impulses simultaneously corresponding, respectively, to the lregistered digits.

35. In combination, registering apparatus arranged to register a pair of dig1ts,'a sender operable under the control of sald reg- RUDOLPH F. STEHLIK.

istering apparatus to send two groups of impulses simultaneously corresponding, respectively, to the registered digits, and a pair of receiving devices arranged to receive the two groups of impulses, respectively.

36. In combination, registering apparatus arranged to register a plurality of digits,

and a sending device operable to send a plurality of groups of impulses simultaneously, said groups of impulses being transmitted under the control of the registering apparatus and corresponding, rpectivel to a group of registered digits, said sen 'ng device eing operable su sequently to send a. second group of series of impulses corresponding, respectively, to digits recorded on said registering apparatus.

37. In combination, a plurality of separate registering devices, anim ulse transmitter, two conductors outgoing om said impulse transmitter, and means for operating said transmitter to send two groups of impulses simultaneously over` said outgoing conductors, res actively, and under t e control, respective y, of a pair of said registering devices,

38.` In combination, a digit transmitter a pair oi outgoing conductors, and means or operating said transmitter to send impulses over one of said conductors corresponding to a digit, and for operating said transmitter to simultaneously send impulses over the other outgoing conductor corresponding to a diderent igit.,

39.. A register transmitter comprising registering apparatus, a plurality of outgoing circuits over which digit impulses are transmitted, and a separate relay for each outgoing conductor, together with circuit arrangements for operating the said relays to 

